What's a Freight Class?
When you ship products via LTL (Less-Than-Truckload), your shipment gets assigned a
freight class
, a standardized code between 50 and 400 that carriers use to determine your shipping rate. Carriers use this code to price shipments based on what you're sending and how it handles in transit.
In July 2025, the NMFTA streamlined this into a
13-tier density-based scale
(down from 18 classes).
Class 50
covers the densest, easiest-to-handle freight and carries the lowest rates.
Class 400
covers the lightest, bulkiest items and carries the highest. Knowing where your shipment falls helps you budget accurately and avoid reclassification fees.
The classification system was created by the National Motor Freight Traffic Association (NMFTA) and is used by virtually every LTL carrier in North America. Whether you're shipping a pallet (skid) of canned goods or a crate of electronics, your freight class directly impacts what you pay.
How to Calculate Your Freight Class
Freight class is primarily based on
density
: the relationship between your shipment's weight and the space it occupies. Here's how to calculate it in three steps:
Once you have your density in pounds per cubic foot, match it to a freight class using the reference chart above, or enter your dimensions and weight into the calculator to get your result instantly.
What Determines Your Freight Class?
While density is the most common factor (and what our calculator uses), carriers may evaluate four characteristics when classifying your shipment.
Density
The weight per cubic foot of your shipment. This is the primary factor for most freight and the basis for density-based classification. Heavier, more compact shipments qualify for a lower class and a lower rate.
Stowability
How easily your freight can be arranged alongside other shipments on the truck. Standard pallets stow easily. Irregular shapes, oversized items, or hazardous goods are harder to stow and may result in a higher class.
Handling
Whether your shipment requires special equipment or attention during loading and transport. Freight that needs extra handling (fragile goods, temperature-sensitive products) may be classified higher.
Liability
The risk associated with shipping your goods, including their value, fragility, and susceptibility to damage or theft. Higher-value or more perishable items carry more liability for the carrier.
For most standard shipments, density alone determines the class. However, certain commodities like hazardous materials, fine art, or live plants may be assigned a fixed class regardless of their density.
Worked Example
Let's say you're shipping a pallet (sometimes called a skid) of packaged goods. The shipment measures
48" × 40" × 36"
and weighs
275 lbs
. Here's how to find the freight class:
At Class 125, this shipment falls in the mid-range, common for items like small appliances and vending machines. If you could reduce the box size or add more weight to the pallet, you might push the density above 8 and qualify for Class 100, which would mean a lower shipping rate.
How right-sizing helps
Now imagine you swap that oversized 48" × 40" × 36" box for a
custom-sized box
that fits snugly at
40" × 30" × 24"
, same 275 lbs:
By right-sizing the packaging, this shipment drops from Class 125 to Class 70, a meaningful reduction in per-shipment cost from eliminating wasted cube. For recurring shipments, the savings compound quickly.
Tips for Reducing Your Shipping Costs
Your freight class directly impacts your bottom line. Here are a few practical ways to optimize your shipments and potentially qualify for a lower class.
Right-size your packaging
Use the smallest box or crate that safely fits your product. Eliminating void space increases density, which can move you into a lower freight class. This is one of the most straightforward optimizations, and it's what
custom packaging
is designed for.
Palletize efficiently
Stack cartons to maximize pallet cube. A tightly packed, shrink-wrapped pallet will yield a noticeably better density than loosely stacked boxes.
Consolidate smaller shipments
Rather than sending multiple small packages individually, combine them onto a single pallet. More weight on the same footprint means better density.
Measure accurately
Carriers will re-weigh and re-measure at the terminal. If your actual dimensions don't match what you declared, expect reclassification fees and adjusted invoices.
Compare quotes from multiple carriers
Different LTL carriers price the same freight class differently. It pays to compare rates, especially on recurring lanes.
Frequently Asked Questions
Why does freight class matter?
Freight class is one of the primary factors in your LTL rate. Declaring the wrong class can trigger reclassification and additional charges. Knowing your class upfront helps you quote accurately and avoid billing adjustments.
Is this calculator 100% accurate?
This calculator provides a
density-based estimate
, which is how most shipments are classified. However, certain commodity types have a fixed class that overrides the density calculation. We always recommend confirming your freight class with your carrier before shipping.
What's the difference between LTL and FTL?
LTL (Less-Than-Truckload)
is when your shipment shares truck space with other shippers' freight. Freight class applies to LTL shipments.
FTL (Full Truckload)
is when you book the entire truck. Freight class typically doesn't apply to FTL because you're paying for the whole trailer.
Can I change my freight class?
You can't arbitrarily select a class, but you can influence it. By optimizing your packaging to increase density (right-sizing boxes, eliminating void space, and palletizing more efficiently) you can legitimately qualify for a lower, less costly class.
